I\'m using ASP.NET Boilerplate for one of my application. The application was on 3.5.0 version of Abp and the template was ASP.NET Core with MVC. I recently upgraded it to 3
Set it in Startup.cs > ConfigureServices() method
services.PostConfigure<MvcJsonOptions>(options => { options.SerializerSettings.ContractResolver = new DefaultContractResolver(); });